1. Field of the Invention
The present invention relates to equipment for repairing damage to piping at places with difficult access, e.g. damage to piping buried in the ground. More specifically, the invention refers to a repair sleeve which may be inserted in such piping from openings in access gullies and the like, and which readily and effectively forms a supplementary conduit part inside the piping covering the inner wall of the damaged place. The invention also includes an insertion device for such sleeves.
2. Description of the Related Art
It is quite often the case with wastewater pipes that due to settling they crack, and joints between pipes become leaky. The consequence is that wastewater leaks out and pollutes the surrounding ground. On the other hand, it also happens that ground water and rain water come into the pipes through the damaged areas which results in that the volume of wastewater increases. The latter problem is a very important one, since the unpolluted water finding its way into the pipe accompanies the wastewater to the sewage treatment plant, where it increases the amount of wastewater which must be treated. In turn, this can result in that the plant capacity is exceeded, and unsatisfactorily purified water will be released to the recipient. Even if the plant capacity is not exceeded there is still the cost of treating an unnecessary large volume of wastewater, a large proportion of which did not need to be treated.
There are also many cases where roots from trees and other vegetation in the vicinity of wastewater pipes are attracted towards leaks in it. This is because the ground there is damp and also rich in nutritive substances. Some of these roots find their way into the cracks or apertures in the pipes and cause them to become larger as the roots grow thicker and thicker. Not only that, but the roots in the pipes obstruct the staisfactory flow of wastewater through them, and can also result in total blockage.
Many solutions of the above-mentioned problems have been sought, but no previous solution has been regarded as fully viable. The usual method of repair is therefore still to excavate round the damage, at great expense and trouble, to uncover the pipe and carry out some form of repair, preferably such as replacing damaged section of pipe.
In the state of the art today, it is usual to examine such piping with the aid of a remotely controlled TV-type camera to determine the occurrance of damage, its extent and location. There is also conventional equipment for cutting off and removing roots in the pipe, all this work starting from the mouth of the piping in inspection wells, access gullies and the like.
It is not necessary to be skilled in the art to understand that if damage of the kind mentioned could be remedied from inside the piping without excavation, then large economic savings could be made. Furthermore, all the trouble caused in communications as a result of excavating streets and roads would be avoided.
One attempt to find a solution to the above-mentioned problems without too extensive excavation is the so-called relining technique, which is to insert inner tubes into existing pipes. From the material aspect this means costs which are substantially just as great as for laying new pipes. On the other hand, it is not necessary to dig up streets and roads, except at the places where pipelaying starts, i.e. preferably in connection with inspection wells and the like. Relining is not usually practised for repairing sporadically occurring damage, and it is primarily used for the prevention of damage to older piping, since the insertion of the inner tubes requires certain special measures, e.g. excavation, for their insertion.